Reduced LOXL3 Expression Disrupts Microtubule Acetylation and Drives TP53-Dependent Cell Fate in Glioblastoma

Glioblastoma (GBM) is the most aggressive primary brain tumor, marked by molecular heterogeneity and poor clinical prognosis. Lysyl oxidase-like 3 (LOXL3) is frequently upregulated in GBM, but its mechanistic contribution remains insufficiently defined. Here, we investigated the functional role of LOXL3 in GBM using CRISPR-Cas9-mediated LOXL3 knockdown in two genetically distinct GBM cell lines: U87MG (wild-type <i>TP53</i>) and U251 (mutant <i>TP53</i>). Reduced LOXL3 expression markedly reduced α-tubulin acetylation, particularly in U87MG cells, and downregulated genes involved in cell cycle progression and proliferation. Both cell lines exhibited mitotic defects, including delayed cell cycle progression and spindle abnormalities; however, cell fate diverged according to <i>TP53</i> status. U87MG cells, sustained spindle checkpoint activation triggered a p53-dependent spindle checkpoint response culminating in apoptosis, while U251 cells underwent mitotic slippage and senescence. Transcriptomic analyses confirmed differential regulation of apoptosis versus senescence pathways in accordance with <i>TP53</i> functionality. Additionally, reduced LOXL3 expression markedly impaired adhesion and migration in U87MG cells, whereas U251 cells were minimally affected, consistent with more pronounced microtubule destabilization. Collectively, these findings identify that LOXL3 is a key regulator of microtubule homeostasis, mitotic fidelity, adhesion, and invasive behavior in GBM. Targeting LOXL3 may therefore provide a therapeutic opportunity for genotype-informed intervention in GBM.